This invention relates generally to underwater photography, and more particularly, to improvements in articulation and adjustability of underwater camera arm assemblies.
Underwater photography has developed into a burgeoning sport for the amateur and is of ever-increasing importance to offshore oil drilling and well repair. Equipment used for still photography includes a camera which can be either a standard land camera enclosed in a watertight housing with waterproof glands and levers for its operation or a self-contained underwater camera. As used herein, the term "camera" will apply to either type.
As the photographer descends into the ocean depths, most colors quickly disappear. In ocean water as shallow as 50 feet, all objects appear as a monochrome blue-grey and light levels drop drastically. For this reason, an artificial light is a practical necessity. This is accomplished by use of an electronic flash unit built specifically for use underwater with a cord connected to the camera to trigger the flash as the shutter is released. In underwater parlance these flash units are known as "strobes".
The camera underwater is typically handheld and levers are manipulated with both hands. A diver seldom stands on the sea bottom. More likely he adjusts his weight so that he floats somewhere above the bottom while photographing.
Since the strobe must be aimed directionally to properly light the subject, another critical piece of necessary equipment is the "strobe-arm", the linkage of members used to position the flash unit with relationship to the camera. Motion picture cameras and video cameras are also used underwater in watertight housings. Lighting is also required for proper exposure and color correction. Again, an important piece of equipment is the leverage system to maintain a light source at proper distance and relationship to the camera.
In contrast to above-water photography, strobe units cannot achieve acceptable results when mounted in close proximity to the picture taking lens. When this is attempted, it results in intensely illuminating all the miscellaneous dirt and organic particles suspended in the water column directly ahead of the lens, creating the illusion of brightly lighted snow between the camera and the subject. The picture is then rendered useless. This effect is called "scatter".
It is known to use a system of rods or levers to suspend a strobe at a point as far away from the camera as thirty inches or as close as two inches. This distance depends upon the nature of the subject, and whether the photographer intends to take a picture of a large animal or scene, or a very small subject. In the latter instance, modern underwater cameras are capable of one to one (1 to 1) performance, meaning capable of one to one (1 to 1) performance, meaning that the subject can be reproduced at life size on the film.
Since there are innumerable possibilities facing an underwater photographer when he enters the sea, the optimum equipment will allow him to choose to place his strobe in any number of positions with regard to distance from the subject and from the lens, and at any angle with regard to the above. At the same time, his two major items of equipment, his strobe and camera, must have an ability to be locked into a position so that it requires an overt act on the photographer's part to alter this relationship. Ocean wave action and severe underwater currents tend at times to move the strobe into an unintended position as the diver moves from place to place, and because of lack of readiness, cause the photographer to miss an important picture or fail to light the subject properly.
Since the first attempt to light an underwater photograph, made late in the nineteenth century by using a watertight wooden box with gun powder supplying the illumination, man has grappled with the problem of how to support the light in relationship to the camera. Many inventions and adaptions have been supplied, each with some merit, but each also failing to do the complete job. One of the earliest modern day support arms was designed by Rolliflex Camera Company and consisted of a tubular rod attachment to the housed camera terminating in a ball. Another similar tube was attached to the strobe or flashbulb holder, with its lower end terminating in a similar ball. The two balls were clamped between two flat pieces joined in the center by a clamping screw. Each of the flat pieces had depressions which captured the balls and exerted pressure upon the balls as the clamping screw was tightened. These pieces may be made of relatively thick metal and designed to be as short as possible to avoid the effects of the bending moment of the clamping screw. Typically, the distance between the centers of the two balls is less than 1.5 inches.
Since it can be rotated and/or pivoted around the lower lever ball, this system provided a degree of mobility for the upper end of the lever system. The major drawback of this design is its lack of rigidity. It is impossible to attain sufficient pressure on the balls to keep them from moving even under a small load. This is due to the divided nature of the direct force of the clamping screw, one half of the total force being supplied to each ball. A second disadvantage is the fact that it requires more pressure than can be generated with a single hand screw to prevent movement of the levered arms. Another limitation is found in the circumstance that the strobe unit can only be deployed in an arc swung around the upper end of the lower or fixed ball. The support provided is adequate in quiet water when the strobe unit is nearly at equilibrium with its weight supported by water, but does not do a satisfactory job when used in strong currents and ocean turbulence. Above the surface of the water the strobe unit is much too heavy for the double-ball leverage system. Left unrestrained, the strobe will crash into the underwater camera that is being supported by the diver's hands with possible damage to one or both units. There is also a possibility of diver injury due to a scissors-like action of the levers.
A further disadvantage is the prior lack of incremental adjustment. Since the flat pieces clamping the two balls ar very rigid and do not flex when the clamping screw is loosened even slightly, the frictional pressure on the balls is reduced dramatically and the system collapses. Thus, the diver-photographer is often seen underwater on his knees using both hands to grapple with the task of holding the strobe and camera in correct relationship while attempting to tighten the clamping screw.
There are a number of other devices that use sliding or telescoping tubes to accomplish the desired result. Typically, if they are strong enough, they are awkward to use and very bulky. If they are lighter and more compact, they are also flimsy and offer limited support.
A major disadvantage to telescoping devices is that when used close to the camera, the reversed ends of the telescoped tubes protrude to the rear and interfere extensively with positioning the camera and the body and head of the photographer.
None of the present devices used for support to my knowledge permit the positioning of the strobe in extreme proximity to the camera lens, in locations anywhere in the 360 degrees available when looking directly into the camera lens. This is important since light attenuates rapidly underwater and only by bringing the strobe to a position as close as one to three inches from the subject can the photograph be expose at a numerically high f-stop, maintaining good depth of field and high color saturation of the film. While underwater close-up photographers attempt to do this, many times there are protuberances that interfere with equipment placement when using current strobe arms. As a result, many photographers resort to removing the strobe and arm and hand-hold the strobe in the proper position. This results in an imprecise alignment and the result is often unusable.